An agitating ball mill of this type is shown in FIG. 1 of DE 44 12 408 A1. This agitating ball mill comprises a double-walled comminution vessel which is suitable for cooling. Within the comminution vessel the agitating shaft arranged coaxially to the comminution vessel is connected with a gearing and a drive. In its lid, the comminution vessel has a comminution stock inlet and, centrally in its base, a comminution stock outlet. The product enters the comminution chamber via the inlet where it is worked through the comminution media present in the comminution chamber. To this end, the comminution discs provided with holes and located on the agitating shaft put the comminution media in motion as a result of which the energy acting from the motor on to the comminution discs is transmitted to the comminution media. The kinetic energy available for this results in the dispersion or comminution of the product introduced in the comminution vessel. Depending on how the agitating ball mill is operated, whether according to the single pass or multiple pass method, the product either in its desired final fineness or as intermediate product finally reaches the area of a pre-classifying stage which holds back in the comminution chamber the comminution media and, if applicable, also products in the corresponding size. In addition to the pre-classifier a separating device can also be provided.
From DD 217 434 B1 a vertically arranged agitating ball mill is known. This agitating ball mill works with an agitating shaft on which a screw-shaped comminution element is fastened. In the inlet area of the mill is located a pre-crushing device connected with the agitating shaft, which consists of a crushing cone and a crushing ring fastened to the comminution vessel wall. The comminution stock or feedstock directly reaches the top of the crushing cone via a screw conveyor and from there into the crushing gap. Following completed pre-crushing the material falls into the comminution vessel in which it is worked by the agitating shaft and the comminution media present in the comminution vessel. The filling level height in the comminution vessel is monitored via a filling level measuring device. This is not possible with horizontally arranged mills and with mills whose comminution chamber is completely utilised. In these cases, the comminution stock reaches the area of the pre-crushing device with the comminution media.
The objective of the invention is to combine a comminution and dispersion device with a pre-crushing device which is largely protected against wear that can be caused by the comminution stock/comminution media mixture.